Did the flagging behavior in LR Classic CC change in Survey mode?

To eliminate the unwanted photos, in the library module, I used to select some of the similar photos, go to survey mode(N) and then reject (X) those I didn’t want. Lets say I’ve 6 images on the screen in survey mode, I select one and hit X, it used to flag only that photo. Then I used to move to the next one in that set of 6 and decide.  But recently this behavior has changed. When I hit X on one of those 6 photos, it is marking all those 6 as rejected. This is happening with pick and reject. Now to reject only one photo, I’m going back to grid(G) and selecting the image and flagging it. This process is very time consuming.

I’m wondering if the LR has changed the behavior or I happened hit some keys that might have changed the behavior. If you guys know how to go back to the original behavior, please let me know.